A report drawn up by the European Defence Agency (EDA), to be discussed by EU defence ministers at an informal meeting in northern Finland next week (2-3 October), will warn that current demographic and economic trends pose serious challenges for how armed forces are organised and structured.

Among the scenarios put forward in the “long-term vision document” is the possibility of current force sizes being unsustainable by 2025 because of the difficulty in getting recruits of working age. By then, the average age in the EU will be 45.

If current troop levels were maintained, the cost of competing for recruits would raise personnel costs well above the current level of 50% of defence spending, a proportion that many already consider too high.

One solution, according to the chief executive of the EDA, Nick Witney, would be to reduce troop numbers and focus on other ways of delivering force.

While admitting that the report paints a bleak picture of the future, Witney said he hoped the document would form an “agreed baseline” for future thinking on where armed forces were heading.

He wants the document to help co-ordination on future military procurement. The document asserts that Europe will be “older, less pre-eminently prosperous and living in a difficult neighbourhood”.

“Every day across Europe decisions are taken which will influence what kind of defence forces we have in 20 years’ time,” said Witney, adding that procurement decisions of the 1970s still had a profound impact on the state of Europe’s armed forces today.

If agreed by ministers, the report is expected to be published on Tuesday (3 October).